Rotary core barrel



March 19, 1935. R, cv BAKER 1,994,847

ROTARY GORE BARREL Filed June 7, 1933 2 Sheets-Sheet 1 F 0.2 153%.! F p. 3

i T W w ATTORNEYS.

March 19, 1935. Q BAKER 1,994,847

ROTARY CORE BARREL Filed June 7, 1933 2 Sheets-Sheet 2 Q g w F M4 -2,z

lg; 1|, 49 A! I Y 3 I Q 27 {/0 a? ii IN V EN TOR. MW A2 ATTORNEYS.

Patented Mar. 19, 1935 UNITED STATES nomnr cons BARREL Reuben C. Baker, Coalinga, CaliL, assignor to Baker Oil Tools, Inc., Huntington Park, Calif., a. corporation of California Application June 7, 1933, Serial No. 674,652

8 Claims.

This invention relates to rotary core barrels such as are employed for taking samples or cores in advance of the drilling during thesinking of deep oil wells and pertains more particu- 5 larly to means for retaining the core in the tube after it has been taken and while the core barrel is being drawn from the well.

In general, core barrels consist of an outer drill barrel suspended from a drill stem and lit-- ted with a cutter head to penetrate the formation from which the core is to be taken. The cutter head cuts away an annular section of the formation, leaving undisturbed a central core. A core tube 'is mounted within the drill barrel and is normally open at its lower end to receive the core. The lower open end of the core tube is fitted with means known as a core retainer which serves to pinch ofi .the core after it has been received in the tube and retain it in the tube as it is drawn from the well.

In practice, the core barrel must be lowered or run in the well with the open end of the core tube foremost. Consequently, heavy mud, drillings and other foreign substances often enter the core tube. The upper end of the core tube is usually provided with a check valve to permit escape of ordinary drilling fluid as the tube re= ceives the core but this valve is not large enough to accommodate foreign matter that may enter through the lower end of the core tube, and consequently this matter remains in the tube ob-= structing a core as it is being taken.

It is the object of the present invention to provide an improved core barrel in which the core tube is fitted with a core retainerthat is normally opened only during the drilling operation so that the retainer serves to prevent entry of obstructing foreign substances into the core tube during running in of the core barrel as well as m to pinch d and retain the core in the core tube alter the core is taken.

One form which the invention may assume is exemplified in the following description and illustrated by way of example in the accompanying drawings, in which:

Fig. l. is a central vertical section of a portion of a core barrel constructed in accordance with my invention.

lfig. 2 is a similar section of the upper end of the same core barrel.

Fig. 3 is a similar. section of the lower end of the same core barrel. v

Fig. i is a fragmentary section of the core barrel showing the position assumed by the parts thereof during the drilling operation.

Fig. 5 is a transverse section taken on the line V-V of Fig. 4.

Fig. 6 is an enlarged fragmentary section of a portion of the lower end of the core barrel illustrating the construction of the core retaining 5 mechanism.

Referring more particularly to the accompanying drawings, Figures 1, 2 and 3 will be considered as a single view, Fig. 1 being the central portion of a core barrel; Fig. 2 the upper end thereof and Fig. 3 the lower end thereof. The drill barrel generally indicated at 10 is suspended in the usual manner on a drill string 11 by means of which it may be rotated. The lower end of the drill barrel is fitted with a cutter head generally indicated at 12 so constructed that upon rotary motion of the drill barrel an annulus is cut in the formation from which a core is to be taken. A core tube 14 is disposed within the drill barrel to receive the core as it is formed by the operation of the cutter head 12.

The lower end of the core tube is provided with core retaining mechanism 15 and the upper end thereof is fitted with the usual check valve 16 so that as the core tube is lowered over the core, fluid within the tube may escape.

Means for supporting the core tube within the barrel and for raising and lowering it relative to the barrel are shown in Fig. 1. A centrally bored head 17 is held concentric to the barrel and retained against vertical displacement therein by means of a shoulder 18 in the barrel and set screws 19 threaded through openings in the side of the barrel, which openings are closed by a second pair of set screws 20 for protection of their threads. A ram 21 provided with cup leathers 22 is reciprocable within the barrel and carries a depending rod 23 extending downwardly through the head l'l'. A pin 21a on one of the set screws 19 projects into an elongated slot 22a in the side of the ram, preventing rotation of the ram in the barrel.

A sub 24 is connected with the upper end of the core tube and carries a sleeve 25 mounted for sliding movement over the lower end of the head 4 17. This lower end of the head 17 is fitted, as shown in Figs. 1, 4 and 5, with three or more radially disposed gears 26, these gears being carried on pins 27 extending through relieved portions 28 formed about the periphery of the head 17 and extending from the outer surface thereof inwardly to the central bore in which the rod 23 is disposed.

The rod 23 is exteriorly. notched and the sleeve 25 is similarly notched on its inner surface, the notches in the rod and sleeve being provided for registry with the teeth of the gears 26 and acting in the nature of rack bars. It should be noted, however, that as the notches in the bar 23 and in the sleeve 25 areextended to completely encircle these members, they permit free rotation of the core tube relative to the head 17 therefore serving as a swivel connection between the core tube and the drill barrel so that as the drill barrel is rotated, the core tube may remain relatively stationary and move down- .wardly over the core as it is out without disturbing the same. 1

Due to the connection between the ram 21 and the core tube formed by the gears 26, downward movement of the ram relative to the head 17 imparts rotation to the gears 26, which rotation of the gears causes upward movement of the core tube due to the engagement of the gears with the notches formed on the interior of the sleeve 25.

The ram 21 is centrally bored as at 29 and provided with circumferentially spaced ports 30 for the passage of drilling fluid to lubricate the teeth of the cutter head. Therefore, in operation of the core barrel, when drilling fluid is pumped downwardly through the drill stem, the pressure of the fluid acts upon the head of the ram 21 to move it downwardly relative to the core barrel, this downward movement causing lifting of the core tube as above described. A portion of the drilling fluid, however, passes through the central bore 29 of the ram, then outwardly through the ports 30 and downwardly through the annular passage between the exterior of the core tube assembly and the inner wall of the drill barrel to lubricate the cutter head teeth.

Referring again to the core retaining mechanism 15 disposed at the lower end of the core tube, this mechanism consists of a segmental core retainer composed of a set of segments 31 pivoted for swinging movement radially of the core tube. The segments 31 are shown as four in number but there may be more or less if desired. .These segments 31 are so shaped that when they are swung inwardly at their lower ends, they cooperate, as shown in Fig. 3 of the drawings, to form a cup shaped retainer substantially closing the lower end of the core tube. When swung outwardly about their pivots, the segments 31 assume the position shown in Fig. 4 of the drawings and in this position permit fre passage of the core into the core tube.

A sleeve 32 is disposed for sliding movement over the lower end of the core tube and comprises an upper ring 33 and a lower ring 34. The sleeve is provided with cut-away portions, as shown, adjacent the pivotal connections of the retainer segments 31 to permit swinging movement thereof.

Each of the segments 31 is provided with an exterior cam like projection 35 engageable with the lower ring 34 of the sleeve 32 to impart inward swinging movement to the segments when the core tube moves downwardly relative to the sleeve. When the core tube is lifted relative to the sleeve, the upper ring 33 of the sleeve engages rounded shoulders 36 on the segments 31 and by engagement with these shoulders swings them to an outward or open position, unobstructing the passage of the core into the core tube. In the operation of the device, the core barrel is first run into the well from which a core is to be taken. During the running in of the core barrel, no fluid is pumped thereto and conseduently the core tube moves by gravity to its lowermost position, as illustrated in Fig. 3, so that the cup shaped retainer forms a closure for its lower end. Thus, in running in the core barrel,

.the lower end of the core tube is closed sufficiently to exclude such foreign substance that would, if received by the core tube, tend to obstruct free passage of the core thereinto.

, When the core barrel reaches the point in the well from which the core is to be taken, the drilling operation is commenced and drilling fluid is pumped downwardly through the drill stein to lubricate the teeth on the cutter head as they perform their cutting action. The pressure of the drilling fluid, being exerted on the head of the ring 33 and the segments are moved to their open position so that the core may be received by the core tube.

When a core of the desired length has been cut and received by the core tube, the drilling is ceased and pressure upon the drilling fluid is relieved. When this pressure, which during the drilling operation serves to maintain the core tube in its uppermost position, is relieved, the core tube again gravitates to its lower position illustrated in Fig. 3 and the segments 31 are again moved inwardly by engagement of the earns 35 against the ring 34. This movement of the retainer segments serves to pinch off or cut the core and the retainer segments, being in this position, maintain the core in the core tube while the entire assembly is withdrawn from the well.

While I have shown the preferred form of my invention, it is to be understood that various changes may be made in its construction by those skilled in the art without departing from the spirit of the invention as deflned in the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A core barrel comprising a drill barrel and a core tube mounted for limited vertical movement therein, a ram in the drill barrel adapted to be forced downwardly by fluid pressure, and means connecting the ram and core tube whereby downward movement of the ram will impart upward movement to the. core tube.

2. A core barrel comprising a drill barrel and a core tube mounted for vertical movement therein, core retaining mechanism at the lower end of the core tube, means whereby upward movement of the core tube will cause said mechanism to open, a ramin the drill barrel adapted to be forced downwardly by fluid pressure, and means connecting the ram and core tube whereby downward movement of the ram will impart upward movement to the core tube.

3. A core barrel comprising a drill barrel and a core tube mounted for vertical movement therein, core retaining mechanism at the lower end of the core tube, means whereby upward movement of the core tube will cause said mechanism to open and downward movement thereof will cause said mechanism to close, a ram in the drill barrel adapted to be forced downwardly by fluid pressure, and means connecting the ram and core tube whereby downward movement of the ram will impart upward movement to the core tube, said core tube moving downwardly by gravity to close said core retaining mechanism when pressure on the fluid in the drill barrel is relieved.

4. A core barrel comprising a drill barrel, a hollow head within said drill barrel and coaxial therewith, a core tube inthe barrel, a sleeve supporting said core tube and arranged to slip over the exterior of said head, aplurality oi radially positioned gears in said head, a grooved surface on the interior of said sleeve in mesh with said gears whereby rotation of the gears will impart vertical movement to the core tube, a ram in the drill barrel above said head and a grooved rod depending from said ram and meshing with said gears to rotate them when fluid pressure is applied to the ram, core retainer mechanism on the lower end of said core tube, and means actuated by raising and lowering of the core tube to open and close said mechanism.

5. A core barrel comprising a drill barrel, a core tube mounted for vertical reciprocation within the drill barrel, a core retainer at the lower end of the core tube, means cooperating with the core retainer to move the same to retaining position when the core tube is in its lowermost position and to open the core retainer when the core tube is elevated from its lowermost position, and fluid pressure actuated means in the drill barrel and connected to the core tube for elevating the same from its lowermost position when fluid pressure is created in the drill barrel.

6. A core barrel comprising a drill barrel, a core tube mounted for vertical reciprocation within the drill barrel, a core retainer at the lower end of thecore tube, means cooperating with the core retainer to move the same to retaining position when the core tube is in its lowermost position and to open the core retainer when the core tube is elevated from its lowermost position,

and fluid pressure actuated means in the drill barrel and connected to the core tube for elevat-'- ing theisame from its lowermost position when fluidpressure is created in the drill barrel, said fluid pressure actuated means enabling fluid under pressure to be pumped downwardly through the drill barrel and around the core tube.

7. A core barrel comprising a drill barrel, a core tube mounted coaxially within the core barrel but of an external diameter less than the internal diameter the drill barrel, a supporting means secured in the drill barrel for supporting the core barrel but enabling the same to reciprocate axially, a core retainer at thelower end of the core mbe, mechanism at the lower end of the drill barrel cooperating with the retainer to move the same to retaining position when the tube is in its lowermost position and to open the retainer when the core tube is elevated from its lowermost position, and fluid pressure actuated means in the drill barrel operatively connected to the core tube to elevate the same from its lowermost position when fluid pressure is created in the drill barrel.

8. A core ,barrel comprising a drill barrel, a core tube moimted coaxially within the core barrel but of an external diameter less than the internal diameter of the drill barrel, a supporting means secured in the drill barrel for supporting the core barrel but enabling the same to reciprocate axially, a core retainer at the lower end of the core tube, mechanism at the lower end of the drill barrel cooperating with the retainer to move the same to retaining position when the tube is in its lowermost position and to open the retainer when the core tube is elevated from its 

